My object becomes darker during animation
So, when you generate objects, you made them without normals. I don't want to say, that they have no normals completely, because mesh can't be without normals. What I see, that all normals are rotated in the same vector, so your objects look completely flat:

But what causes the jittering in colors? This vector is different from one object to another. This mean that your object is shaded completely flat as a single plane can be, but each time the plane is rotated in a different angle.
So, how to fix that, depends on your code. I guess you should use update function (update(calc_edges=True)) to update normals, but maybe I'm wrong. I noted, that clearing custom normal data (in &quot;Geometry data&quot; section) force normals to be recalculated:

You might be wondered why if your object shaded flat, you still see some shading in the render? It is because ambient occlusion still have effect even without proper normals